A home base station is a small-size low-power base station, which is mainly used in small-scale indoor places such as homes and offices and so on. The home base station connects to a core network of the mobile operator in wired access ways such as indoor cable, Digital Subscriber Loop (DSL) or optical fiber and so on, which provides access services based on a wireless mobile communication network for specific users. It is an effective supplement to the existing network deployment, which can effectively improve the indoor voice and high-speed data service coverage. The home base station has many advantages, such as low costs, low power, simple access, plug and play, saving backhaul, being easily compatible with the existing terminals, and being able to improve the network coverage rate and so on.
The home base station in a Long Term Evolution (LTE) system defined by the Third Generation Partnership Projects (3GPP) standards organization is called as a home eNB (HeNB). Functions supported by the HeNB are basically identical with functions of an eNB, and processes between the HeNB and an Evolved Packet Core network (EPC) are basically identical with processes between the eNB and the EPC. Since the HeNB is normally deployed without network planning of the mobile operator, a coverage area is small and the number of HeNBs is large, therefore, in order to more conveniently manage and support a larger number of HeNBs, in an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) architecture, a new network element—Home eNB Gateway (HeNB GW) may also be introduced in an S1 connection between the HeNB and the EPC, and the HeNB can connect to a Mobility Management Entity (MME) through the HeNB GW as an S1 agent.
In the LTE R10 version, a direct X2 interface (i.e., an X2 interface which is not established by other nodes (such as an agent node)) just exists between HeNBs, and it can be used for load balancing, handover optimization and information interaction and so on, but the X2 interface is not supported between a macro base station (eNB) and a home base station (HeNB). In the LTE R11, a new function entity—X2 gateway (called as X2 GW for short) is introduced. The X2 GW is similar to the HeNB GW and is deployed optionally, an indirect X2 interface can be established through the X2 GW or a direct X2 interfaces is not established through the X2 GW between the eNB and HeNB and between the HeNB and HeNB.
FIG. 1 is a schematic diagram of network architecture of the home base station in a case that the X2 gateway is deployed. The HeNB can connect to the MME through the HeNB GW as an S1 agent. In the LTE R11 version, the HeNB also can connect to a neighboring base station (such as a home base station or a macro base station) through the X2 GW; wherein, both the HeNB GW and X2 GW are deployed optionally. As shown in FIG. 1, an eNB1 establishes indirect X2 interfaces with an HeNB2 and HeNB3 through the X2 gateway, and an indirect X2 interface is established between the HeNB2 and HeNB3 through the X2 gateway. The eNB1 also can establish a direct X2 interface with an HeNB1.
An HeNB can obtain an address of an X2 GW to which the HeNB belongs and an address of an HeNB GW to which the HeNB belongs through an HeNB Management System (HeMS) after power-on, and respectively establishes an X2 connection with the X2 GW and establishes an S1 connection with the HeNB GW. In a case that the X2 GW is deployed, if an indirect connection mode based on the X2 GW is used, the HeNB can establish an X2 connection with an opposite-end base station through the X2 GW.
An eNB can discover a cell under a neighboring base station through an Automatic Neighbor Relation (ANR) function, and establish an X2 connection with the neighboring base station. Specifically, after measuring a stronger signal of a neighboring cell, a UE in an eNB cell sends a measurement report to the HeNB, wherein a Physical Cell Id (PCI), an E-UTRAN Cell Global Identifier (ECGI), a Tracking Area Code (TAC) and a Public Land Mobile Network (PLMN) list and etc. can be carried. If the neighboring cell is a cell under the home base station, a Closed Subscriber Group ID (CSG ID) and a member state of the UE in the neighboring cell also can be carried. After obtaining the ECGI (PLMN ID+cell ID) of the neighboring cell, the eNB judges whether the neighboring cell is a macro cell or a home base station cell through information including the PCI, ECGI or CSG ID and so on; if the neighboring cell is a macro cell, the eNB takes the first 20 bits of a cell ID of the macro cell as its eNB ID; and if the neighboring cell is a home base station cell, it takes all the 28 bits of a cell ID of the home base station cell as its eNB ID. After obtaining an eNB ID of a base station to which the neighboring cell belongs and a Tracking Area Indicator (TAI) (PLMN ID+TAC) of the neighboring cell, the eNB initiates a Transport Network Layer (TNL) address discovery process to obtain a transport layer address of the neighboring cell for establishing an X2 connection.
Since the TNL address discovery process is an S1 interface interaction process, and the X2 GW and HeNB GW are independent network elements and are not jointly set in the same network element, the TNL address discovery process does not go through the X2 GW. If the neighboring cell discovered by the eNB is an HeNB cell, and an indirect X2 connection is required to be established between the eNB and the HeNB through an X2 GW, the eNB needs to obtain a TNL address of the X2 GW to establish the indirect X2 connection with the HeNB through the X2 GW. But in the related art, the eNB cannot obtain an address of the X2 GW connected to the HeNB discovered by the eNB and cannot establish an X2 connection with the HeNB.
Moreover, in consideration of safety aspects, in certain networks, a base station has a “firewall” function, which is used for checking whether an IP address of the source end is authorized to communicate with the base station. In order to implement this function, the base station is required to maintain an Access Control List (ACL), and the list contains legal TNL addresses of opposite-end nodes permitted to communicate with the base station. In the existing LTE standard protocol, an initiating-end base station of the TNL address discovery process can send an address of the initiating-end base station itself to a target-end base station through the flow, which is used for implementing a firewall function of the opposite-end base station. In the subsequent process, only when a TNL address of a source-end network node communicating with the target base station is in an ACL of the target base station, can the target base station communicate with the source-end network node.